1. Field of the Invention
The invention relates to revolution control apparatuses for internal combustion engines (such as diesel engines), and internal combustion engines (hereinafter, referred to as engines) provided with those revolution control apparatuses. In particular, the invention relates to measures for balancing an increase in the responsiveness of the fuel injection system that determines the fuel injection amount through so-called revolution feedback control, and the stability of engine operation.
2. Description of the Related
In the past, the fuel supply systems of multi-cylinder diesel engines disclosed, for example, in Patent Documents 1 and 2 listed below have determined the fuel injection amount from the fuel injection valves through electric control. One example of a method for determining the fuel injection amount has also been to adjust the fuel injection amount according to the manner in which the engine revolution fluctuates. That is, so-called engine revolution feedback control is performed in which the prior engine revolution is recognized when computing the necessary fuel injection amount, and if this recognized engine revolution is lower than a target revolution, then the fuel injection amount is increased, and if this engine revolution is higher than a target revolution, then the fuel injection amount is reduced.
One example of how engine revolution feedback control has been performed to date has been to calculate the engine revolution in the expansion stroke of a cylinder from the time that is required for the crank shaft to rotate by a predetermined angle from the compression upper dead center of that cylinder, and from this to recognize the current engine revolution and then compare the current engine revolution with the target revolution to determine the fuel injection amount. Hereinafter, this engine revolution feedback control is referred to as “immediately prior cylinder feedback control.”
Another example has been to calculate the engine revolution in the expansion stroke of a cylinder from the time that is required for the crank shaft to rotate by a predetermined angle from the compression upper dead center of the cylinder, and from this to recognize that the average value of the revolutions from the cylinder immediately prior to a cylinder before the cylinder immediately prior is the current engine revolution and then compare the current engine revolution with the target revolution in order to determine the fuel injection amount. Hereinafter, this engine revolution feedback control is referred to as “multiple average feedback control.”    Patent Document 1: JP 2001-41090A    Patent Document 2: JP 2002-371889A